A Russian warship will pay a rare visit to San Francisco later this month.

The guided missile cruiser Varyag left Vladivostok on June 4 bound for San Francisco and will arrive on June 20 for a five-day stay.

The cruiser sailed in company with the Russian navy tanker Boris Butoma and the salvage tug Fotiy Krylov. It was not clear whether these two ships will accompany the Varyag to San Francisco.

The Russian ships are commanded by Rear Adm. Vladimir Kasatonov, and the purpose of the visit, which may include other California ports, is to promote U.S.-Russian military cooperation, according to a spokesman for the Russian Pacific Fleet.

No one at the port of San Francisco could remember the last time a Russian naval vessel visited the West Coast, though merchant ships from the Russian Far East occasionally call at San Francisco Bay.

June 20 will be a busy day on the San Francisco waterfront. Three Japanese Self-Defense Force vessels, all warships, are expected that day. If all six vessels arrive that day, it will be the largest number of foreign warships to call at San Francisco in many years.